It looks like you are having trouble with the machine sewing on the top side. Perhaps you are attaching the binding to the back correctly but having trouble turning the corner on the top side. I just posted these pictures on another post, but maybe they will be helpful.
First I cut my binding 2 1/4 inches and press in half with lots of starch. Wetting with starch before I fold helps the fabric stick to it self before pressing and I can get a good press and a stiff binding. After attaching the binding to the back, then fold the binding to the front and place the edge right on the stitching line. I then use my "stitch in the ditch" foot and move my needle from the center position to the right slightly. That way when I run the guide on the stitching line, it catches both the front and the back of the binding equal distance from the edge. The following pictures show how I turn the corner. Hope this helps.
After sewing binding to back, fold to front and pin each corner on the stitch line to hold in place
[ATTACH=CONFIG]183935[/ATTACH]
I do not pin as I sew the sides, just use fingers to hold the binding on top of the stitch line. When approaching the corner, I then use a stilletto to make a crisp miter as shown
[ATTACH=CONFIG]183939[/ATTACH]
When completed, the visible stitch line should be equal from the edge on both sides and the mitered corners should be flat
[ATTACH=CONFIG]183942[/ATTACH]
Use the stilletto to hold the corner down as you slowly take your stitching to the fold, then stop with needle down
[ATTACH=CONFIG]183944[/ATTACH]
After turning the corner and taking a couple stitches, remove the pin and continue to the next corner
[ATTACH=CONFIG]183950[/ATTACH]